How does a doctor repair my orbicularis oculi or is there absolutely no cure?

Often the orbicularis muscle strength cannot be changed, but we can help support the lower eyelid in different ways to improve lid closure. I recommend you see an eyelid specialist in your area.
Best of luck!

What you have not provided us with are your photos. While it is not always possible to make things better than they were before your botched surgery, it is often the case that the right reconstructive surgery can make an enormous difference for your eye comfort, appearance, and the ability of the eyelids to close. I encourage you to study my before and after pictures here on Realself and study the link below. Due the corona virus, we are only seeing urgent patients and post-operative patients. Like many office our surgical counselor is available to speak with you by phone during this time. 

This is a complex problem that needs more detailed evaluation to determine if any procedure can help. Technically we cannot make the orbicularis stronger but there may other treatments that can help to improve eye closure.

These are tough problems to fix.  As you are well aware the lower eyelid tissues are very delicate and prone to the forces and nature of healing. Free-border structures like the eyelids and lips are notorious for having issues post procedure.   There are surgical steps to add tissue to the skin of the eyelids or to the backside of the lid (conjunctiva). Adjusting the medial and lateral canthal ligaments are often performed.  You had mentioned lateral canthoplasty but there may be a need for a medial reconstruction as well.  I have partnered with oculoplastic surgery where they optimize the support structure of the eyelid and I perform an endoscopic mid-face elevation to support the cheek and the lower eyelid as well.

I recommend you consult with multiple oculoplastic surgeons and partner with someone who has a tremendous experience in the reconstructive aspect of the lower eyelid. Someone may brag about they fixed "botched" cases but that does not indicate they are the most qualified. I would seek consultation via referral to reconstructive experts in addition to those who "self-promote". 

I hope this serves to assist.